Light-sensitive material and method of making the same



Patented Dec. 12, 1939 UNITED STATES. l

ATENT OFFICE GET-SENSITIVE MATERIAL MAKING THE S m us'rnon AME 6 Claims.

Our invention relates to light-sensitive layers, to a method of making the same, and to a method of obtaining contrasts therewith.

In the photo-chemical production of contrasts it is known to produce a metal image by means of a photo-sensitive diazonium compound and a metal salt which can be reduced tov form metal in an aqueous solution. For example, it has been proposed to produce in this way a silver image 0 by means of a silver salt, and in the U. 8. Patent 2,067,690 to Alink et al. excellent results are obtained by means of a diazonium compound and a mercurous salt. In the latter case a mercury image is obtained which gives excellent contrasts,

15 and this image can be given a high covering power and a high density by physical development" with a silver salt.

The term "physical development", as used herein and in the claims is to be understood to 0 mean a development in which, prior to the deso a high gamma, which is a disadvantage as regards general use of the method for photographic purposes.

The object of the present invention is to materially reduce the gradation value of the images formed on such materiaL'and for this purpose we use as a support a transparent lyophile film and provide the same with a colloidally-dispersed material which during formation of the image does not, or substantially does not, dissolve in the solution used for the physical development and which causes local variations in the concentration of the photo-sensitive diazonium compound in the film.

As a lyophile film supporting material having a a great afilnity with respect to polar solvents we preferably use regenerated cellulose, but other materials, for instance cellulose derivatives, such as acetyl cellulose and gelatine foils may also be used 50 We have found that when using a film such as described above, the gradation value obtained after development is considerably lower than it would have been without using the invention. This is probably due to the fact that a film according to the invention has the property that, with a homogeneous exposure followed by physical development, local variations of the quantity of the deposited metal forming the image are obtained.

1mm. Application August 1, 1m, Serial 222,536. In Germany August 9, 1937 The colloidally-dispersed material may be either introduced into the support during the manufacture thereof, or formed as a colloidal precipitate in thesupport by'means of a chemical reaction. The gradation value of the image can be controlled within wide limits by varying the quantity of the colloidally-dispersed material contained within the transparent film, and can be made smaller by increasing the quantity of the oolloidally-dispersed material.

In carrying out the invention, the selection of the colloidally-dispersed material used in any particular case depends upon practical considerations. For example, the materials introduced or to be introduced into the support must not react with each other in an undesirable manner, and it is, of course, preferable to use materials which do not cause excessive fogging. Practical circumstances must also be considered for the applicationof the colloidally-dispersed material. For example, if it is desired to form the oolloidallydispersed material by means of aprecipitation reaction, care should be taken'that the concerntration of the solutions are so chosen that the precipitate arises in the film itself. It may occur, for instance, that a material introduced has for the greater part already been expelled by dif-- fusion from the film before the concentration of a second material necessary for the precipitate in the film is sufilcient to produce the precipitate in the film. To avoid this the concentration of this second reagent solution should be made sufflciently strong. Furthermore, in some cases the precipitate might be soluble in an excess of the above-mentioned reagent solution. In such a case, the concentration of the reagent solution must be sufficiently weakto avoid the last-mentioned drawback. If, with a certain precipitation reaction, the relationship of the solubility conditions of the reacting materials are such that suitable concentrations cannot be found, this combination is in the nature of things unsuitable for the preparation of a film according to the invention. In such a case, however, it may be possible to provide the material to be colloidally dispersed, in some other manner in the him, for instance during the manufacture of the support material itself.

From the above it appears that materials which are suitable for carrying out the invention can be selected by one skilled in the art from the point of view of diazonium compound-adsorbing capacity whilst being in the colloidal dispersed state.

In order that the invention may be clearly an readily carried into effect, we shall describe the samein more detail with reference to several examples. 4

Example I a A transparent film consisting of regenerated cellulose of a thickness of about 40a is soaked for several minutes in a nitric solution of bismuth nitrate, which may be prepared in the following manner:

5 gms. of basic bismuth nitrate (BiONOaHzO) are mixed with 2.2 cos. of nitric acid (sp. gr. 1.4); a solid mass arising with the production of heat. Subsequently cos. of water and 2.5 cos. of nitric acid (sp. gr. 1.4) are added in which this solid material dissolves. Upon dilution with 3.2 ccs.

' of nitric acid (sp. gr. 1.4) and 103 cos. of water,

an aqueous solution is produced which contains 5% bismuth nitrate and 4% nitric acid.

The excess solution is then removed by pass- I ing the film between suitable rolls.

The film is then introduced into a solution containing two parts by volume of ethanol (CzHsOH) and one part by volume of water. The film is allowed to remain for 5 to 10 minutes in this solution while agitating the liquid,' and as a result the bismuth nitrate is hydrolised. The adhering excess liquid is removed, and. the film is dried in air.

The film thus prepared is then soaked for several minutes in a solution obtained by mixing:

Diazonium-2 hydroxy-l methyl-6 benzene sulphonic acid-4 gms 2.0 Mercurous nitrate (HgNOaHzO).. gms 2.5 Nitric acid (sp. gr. 1.4) cc 0.75 94% ethanol ccs 86 Water ccs 21 Glycerol ccs 10 quantity of the bismuth compound is added to the film. The color of the image also depends on the quantity of the bismuth compound used, and with a larger quantity the color of the image changes from black to a ratherbrown tone.

Example II A film of regenerated cellulose, provided with a basic bismuth nitrate precipitate in the manner described in Example I, is sensitized by means of the following solution:

Double salt of p-diethylamino-benz ene-diazonium chloride and zinc chloride-..gms.. 2.0 Silver nitrate em 4.1 Tartaric acid g 1.0 Water ccs 65 94% ethanol ccs..; 25 Glycerolccs 10 The adhering excess liquid is removed and the film dried in air.

A metal image is then obtained 'on the film by physical development in the manner described in Example I.

Ea'arizple ZZZ A film is provided with basic bismuth nitrate in the manner described in Example I, and is sensitized by the application of the following solution:

p-Diphenylamino-tlazonium sulphate-gms 5.0 Silver nitrate gms 5.0 Wateros" 175 The film is then treated in the manner described in Example I whereby a metal image is obtained by physical development.

Example IV A film of superficially saponified acetyl cellulose is provided with basic bismuth nitrate in the manner described in Example I and is then sensitized with the following solution:

Diazonium-2 methyl-8 phenol sulphonic acid-4 gms 2.0 Silver nitrate "gms-- 2.5 Mercurous nitrate (HgNOi2H:O)-- gms 3.5 Water -ccs A metal image can be obtained in the film thus obtained by the physical development described in Example I.

Upon comparison of physically-developed" images on films containing bismuth oxy-nitrate with images on films subjected to exactly the same treatments, but with the difference that a bath in nitric acid of 4% is substituted for the bath in the nitric bismuth nitrate solution, it is found that in all of the Examples I to IV above, the gradation value ('7) is decreased. This will be more clearly explained with reference to Table I which gives some comparative data obtained from experiments which we have made.

Table I Gradatlon value 0! images produced Treatment 0! film Film con Film free taining Bi of Bi Example I 3. l 0 Example IL 4. 0 6. 3 Example III 1 3.0 About 6 Example IV 4. l About 6 Example V (a) Bathing for about three minutes in a 1 n.

ammonia solution,

(b) Bathing for three minutes in 0.1 n. caustic soda lye,

(c) Allowed to remain for several hours in a closed drum above a concentrated ammonia solution.

For the three films receiving the treatments a, b, and c respectively, the further treatment is the same; namely, rinsing for about 15 minutes in running water, bathing .for about 15 minutes in distilled Water, blotting between filter paper, and drying in. ail.

For comparison several films (not subject to the treatments at, b, or 0) were rimed only in distilled water (a), and several films were bathed in 0.1 N. caustic soda lye, followed by rinsing in water and bathing in distilled water (e).

All of the films treated in the described manners were sensitized by means of the following manner described in Example I.

In the films containing zirconium the color of the metal image is somewhat bluish.

With such a series the following gradation values were found:

Table II Gradation Treatment value respect.

In contradistinction to films containing bismuth which are often opalescent. films containing zirconium are substantially as transparent as films that have not been treated. I

Example VI Two similar cellulose films were treated according to Example V treatment 0 and sensitized. Subsequently one of these films was bathed for about one minute in ethanol of 55% to which is added 0.1 part by volume of glycerol. After removing the adhering excess liquid, the film was dried in air. The films were then exposed in a similar manner. After physical development, it was found that the film subjected to the aftertreatment is softer than a film which was not treated; the gradation value being 2.0 and 3.4 respectively.

While we have described our invention with reference to certain applications and in connec-' aqueous solution, and means within said portionv to produce local variationsin the concentration of the diazonium compound and to reduce the gradation value of the light-sensitive system. said means comprising a colloidally-dispersed material which is substantially not dissolved by the developing solution during the formation of the image.

2. A light-sensitive material adapted to be physically-developed after exposure bythe application of a developing solution comprising a support of a transparent lyophile colloid of the type of regenerated cellulose and cellulose derivatives, a light-sensitive system within a portion of said support and comprising a diazonium com- I pound and a metal salt which is reducible to a metal in an aqueous solution, and means within said portion to produce. local variations in the concentration of the diazonium compound and to reduce the gradation value of the light-sensitive system, said means comprising a colloidallydispersed material which is substantially not dissolved by the developing solution during the formation of the image.

3. A light-sensitive material adapted to be physically-developed after exposure by the application of a developing solution comprising a support of transparent regenerated cellulose, a lightsensitive system within a portion of said support and comprising a diazonium compound and a metal salt which is reducible to a metal in an aqueous solution, and means within said portion to produce local variations in the concentration of the diazonium compound and to reduce the gradation value of the light-sensitive system, said means comprising a oolloidally-dispersed material which is substantially not dissolved by the developing solution during the formation of the image.

4. A light-sensitive material adapted to be physically-developed after exposure by the application of a developing solution comprising a support of a transparent cellulose derivative of the type of acetyl cellulose and gelatin material, a light-sensitive system within a portion of said support and comprising a diazonium compound and a metal salt which is reducible to a metal in an aqueous solution, and means within said portion to produce local variations in the concentration of the diazonium compound and to reduce. the gradation value of the light-sensitive system, said means comprising a colloidally-dispersed material'which is substantially not dissolved by the developing solution during the formation of the image.

5. A light-sensitive material adapted to be physically developed after exposure by the application of a developing solution comprising a support of a transparent lyophile colloid, a lightsensitive system within a portion of said support and comprising a diazonium compound and a metal salt which is reducible to a metal in an aqueous solution, and means within said portion to produce local variations in the concentration of the diazonium compound and to reduce the gradation value of the light-sensitive system, said means comprising colloidally-dispersed basic bismuth nitrate. I

6. A method of photo-chemically pro d ucing contrasts comprising the steps of placing a diazonium compound within a portion of a support of a transparent lyophile colloid to.form a lightsensitive system, incorporating within the said portion of the support to produce local variations in the concentration of the diazonium compounds coiloidally-dispersed material which is substantially not dissolved in the developing solution, selectively exposing the so-treated support to light, and physically developing the exposed support by applying to said portion a developing solution containing a metal salt reducible to a metal in an aqueous solution. a

. CORNELIS JOHANNES DIPPEL. ROELOF JAN HENDRIX ALINK. KLAAB JANNEB KEUNING. 

